Drop From Space

The ride up

Both vehicles launch as rideshare payloads on a Falcon 9 Transporter-class mission to a ~550 km sun-synchronous orbit. This is a deliberate constraint, and it shaped almost every design decision downstream.

Flying rideshare means accepting the ESPA payload envelope and the standard separation interfaces. It means no dedicated orbit: you go where the bus goes. It means your vehicle has to survive the acoustic and vibration environment of a shared fairing, tolerate a deployment sequence you don't control, and establish attitude and communications on its own after separation, tumbling, with no ground contact for potentially most of an orbit.

In exchange, you get a launch cost measured in hundreds of thousands of dollars per vehicle instead of tens of millions, and a flight opportunity every few months instead of every few years. For a company whose thesis is that orbital logistics should work like terrestrial logistics (scheduled, boring, cheap), designing to the rideshare envelope isn't a compromise. It's the point.

The constraint bites hardest on Thor. A reentry vehicle wants to be dense: thermal protection scales with surface area, and structural mass scales with volume, so the ballistic coefficient you can achieve inside an ESPA-class envelope defines your entire entry corridor. We'll come back to that.

Tessera-1: the factory

Tessera-1 is built around a simple observation: microgravity manufacturing has been demonstrated dozens of times on the ISS, and commercialized approximately zero times at scale. The bottleneck was never the science. It was that every experiment had to fit inside a crewed station's safety envelope, share crew time, and wait years for a return slot on a capsule sized for astronauts.

Tessera removes the station from the equation. It's an uncrewed free-flyer built from hexagonal manufacturing modules, each one a sealed, thermally controlled cell containing a single process. The hexagonal geometry isn't aesthetic. Hex cells tessellate into a honeycomb array that maximizes packing density inside a cylindrical fairing envelope, gives every module three shared structural walls (cutting panel mass roughly in half versus isolated boxes), and creates natural routing channels for power, data, and thermal fluid at the cell vertices. The full production configuration scales to a 120-module array; the flight-one vehicle flies a reduced array to retire the core risks first.

Why does microgravity matter for manufacturing? Three effects, all of which are impossible to switch off on Earth:

Convection disappears. On Earth, any temperature gradient in a fluid drives buoyancy-driven flow: hot material rises, cold sinks. In melt processes like fiber drawing, this convection introduces micro-defects and crystallization. Heavy-metal fluoride glass fibers (the ZBLAN family) drawn in microgravity show orders-of-magnitude lower attenuation than terrestrial equivalents, which is why they're the canonical first product for orbital manufacturing: high value per kilogram, existing terrestrial demand, and a defect mechanism that literally cannot be suppressed under gravity.

Sedimentation disappears. Particles in suspension don't settle. Protein crystals grow larger and more ordered because the depletion zone around a growing crystal isn't constantly disturbed by the crystal sinking through its own solution.

Containers become optional. Levitated, containerless processing means no crucible contamination, relevant for ultra-pure alloys and optical materials.

Each Tessera module runs its process autonomously over a mission phase of weeks to months, with finished product transferred to standardized return cartridges. Which raises the obvious question: how do the cartridges get home?

The downmass problem

Here is the current state of the return market, honestly stated: if your payload isn't flying inside a crew-rated capsule, your options for getting it back from LEO are extremely limited, infrequent, and priced accordingly. Capsule downmass is a scarce resource allocated by station logistics, not a service you can book. Several companies are working on this; we consider that validation, not competition, because the market being created is orders of magnitude larger than the vehicles being built to serve it.

But there's a second, less-discussed dimension to downmass: precision and timing. A capsule splashing down in an ocean recovery zone, on a schedule set by station operations, works fine for science samples. It does not work for time-critical cargo, for delivery to specific ground infrastructure, or for the defense logistics use case, where the ability to place material at a chosen point on Earth, from orbit, within hours of tasking, is a capability that currently does not exist in any inventory.

That capability gap is what Thor XR-1 is designed to close.

Thor XR-1: falling with precision

Thor XR-1 is a hypersonic reentry vehicle with deployable wings. The mission profile has four phases, and each one is governed by a different branch of physics.

Phase 1: Deorbit. From the 550 km parking orbit, Thor performs a retrograde burn of roughly 150–170 m/s to lower its perigee into the upper atmosphere and target an entry corridor. The burn precision here defines everything downstream: the entry flight-path angle at atmospheric interface (120 km) must sit inside a corridor roughly one degree wide. Too shallow and the vehicle skips: insufficient drag to capture, adding thousands of kilometers of downrange error. Too steep and peak heating and deceleration loads exceed the vehicle's structural and thermal margins. We target an entry flight-path angle near −1.5° to −2°, arriving at interface at approximately 7.8 km/s.

Phase 2: Hypersonic entry. Between 120 km and roughly 40 km altitude, Thor is a blunt-body decelerator. At Mach 25, the vehicle doesn't push air aside; it compresses it through a detached bow shock into a plasma layer at temperatures where the dominant heat transfer mechanism shifts from convection toward radiation from the shock layer itself. Peak heat flux on the nose stagnation point reaches the low megawatts per square meter; peak deceleration is in the 4–8 g range depending on the trajectory flown.

Two design decisions dominate this phase. The first is the thermal protection system. The nose cap and windward surfaces use an ablative TPS, material that manages heat by sacrificing itself, pyrolyzing and blowing the reaction products into the boundary layer, which both carries energy away and thickens the layer insulating the structure. Leeward surfaces, which see an order of magnitude less heating, use lightweight ceramic insulation. This split is the standard mass-optimal approach, but the ratio of windward to leeward area is set by the vehicle's hypersonic trim angle of attack, which is where the CFD campaign has focused.

The second decision is control authority. Aerodynamic surfaces are useless in the rarefied upper atmosphere and would be torched at peak heating. Thor flies the hypersonic phase entirely on its reaction control system: cold-gas thrusters arranged for full three-axis authority, sized around the disturbance torques of hypersonic flight rather than the gentler on-orbit environment. The RCS holds the vehicle at its trim angle of attack and executes bank-angle modulation, rolling the lift vector left and right to steer downrange and cross-range while the vehicle is still a plasma-wrapped brick. Bank-angle steering is how a vehicle with a modest lift-to-drag ratio (0.2–0.3 in this regime) converts a ballistic fall into a guided trajectory with hundreds of kilometers of cross-range.

Phase 3: Blackout and the handoff. For roughly 90–120 seconds around peak heating, the plasma sheath around the vehicle attenuates RF communication, the classical reentry blackout. During this window Thor is fully autonomous: inertial navigation propagates the state, the guidance loop keeps flying bank-angle commands against the reference trajectory, and no human is in the loop because no human can be. The guidance algorithm is a predictor-corrector: it continuously re-propagates the trajectory to the target from the current estimated state and adjusts the bank profile to null the miss. This class of algorithm has flight heritage on modern capsules; our contribution is fitting it into a vehicle two orders of magnitude smaller.

Phase 4: Wing deployment and terminal glide. This is Thor's signature maneuver, and the reason "XR" is in the name. Below roughly Mach 2 and 20 km altitude, after dynamic pressure has fallen from its hypersonic peak but while there is still enough energy to fly, Thor deploys its wings.

The deployment problem is an actuator sizing problem before it's an aerodynamics problem. The wings must unfold against transonic dynamic pressure, drive through the aerodynamic hinge moment with margin, and lock into a load-bearing position within a couple of seconds, because during deployment the vehicle transitions through its worst aerodynamic configuration, with asymmetric partial wings and shifting center of pressure. The actuators are sized for the worst-case hinge moment at the high-q corner of the deployment envelope, with mechanical locks that carry flight loads so the actuators don't have to hold torque for the rest of the descent.

Once deployed, the vehicle's lift-to-drag ratio jumps several-fold, and Thor transitions from a decelerator into an aircraft. The terminal glide provides the final tens of kilometers of reach and, critically, the precision. Instead of a ballistic dispersion ellipse measured in kilometers, a gliding vehicle with active terminal guidance targets a landing zone measured in tens of meters. That is the difference between "recover it from the ocean" and "it's on the pad you painted."

Why one launch, two vehicles

Flying Tessera-1 and Thor XR-1 on the same Falcon 9 is not just a cost optimization. It's a demonstration of the full logistics loop in a single mission: mass goes up as raw material and vehicles, value is created on orbit, and finished product comes down to a chosen point on Earth. Up, transform, down.

On flight one, the loop is deliberately decoupled: Tessera manufactures and telemeters its process data; Thor flies its entry profile with an instrumented mass simulator standing in for the return cartridge. Physical cartridge transfer between the vehicles is a later-flight capability, because rendezvous and capture is its own risk pyramid and we refuse to stack unproven risks on top of each other. Flight one exists to answer two questions with flight data instead of simulation: does the factory work, and does the delivery vehicle hit its mark.

What we're testing before we fly

Every claim above is currently supported by analysis, and analysis is where confidence goes to be overestimated. Between now and flight, the campaign looks like this:

• Aerothermodynamics: CFD across the entry envelope, anchored at the trim points, with particular attention to the leeward separation region where heating predictions carry the largest uncertainty, followed by TPS coupon testing under representative heat flux.
• RCS: thruster characterization and hardware-in-the-loop simulation of the full entry, flying the actual guidance software against a six-degree-of-freedom simulation with dispersed atmospheres, winds, and navigation errors: thousands of Monte Carlo entries before one real one.
• Wing deployment: ground deployment testing under simulated aerodynamic hinge moments, through the full temperature range the mechanism will see after soaking through the hypersonic phase.
• Tessera modules: thermal-vacuum campaigns of the manufacturing cells, running the actual processes in the actual flight enclosures, because a process that works on a lab bench and a process that works inside a sealed 10-liter hex cell in vacuum are different processes.

We'll publish results from each of these campaigns as they happen, including the failures, because the failures are where the engineering actually lives.

The point

Launch made orbit reachable. Manufacturing makes orbit valuable. Return makes that value usable. The industry built the first leg; we're building the other two, and building them the way the first one was won: small teams, fast iteration, flight data over paperwork, and vehicles designed to fly often rather than perfectly.

The first Falcon 9 carrying both vehicles is the beginning of that loop. When Thor's wings snap open at 20 kilometers and it flies itself to a point we chose before launch, "drop from space" stops being a concept.

It becomes a service.